Parallel straightedge device



March 3, 1942. H. L. DE LlsLE PARALLEL STRAIGHTEDGE DEVICE FiledApril 19, i940 2 Sheets-Sheet l March 3, 1942.` H. 1 DE L lsLE 2,275,251

PARALL/EL STRAIGHTEDGE DEVICE Filed Apr-11 19, 1940 2 sheets-sheet 2 Patented Mar. 3, 1942 UNITED STATES PATENT OFFICE 2,275,251 PARALLEL STRAIGHTEDGE DEVICE Harold L. De Lisle, Sheboygan, Wis.

Application April 19, 1940, serial Nmasasas s claims. l(o1. ss-so) v i This invention relates to parallel straightedge device and aims to provide an improved and simplified device of the type in which the drawing board has superimposed thereon a slidable straightedge blade, the blade being connected with a cable mounted either above or below the top surface of the board for maintaining the blade in successive parallel positions.

It is desirable to have a single blade which is adaptable for association with drawing boards in which, in some cases, the cable is above the top surface of the board, and, in other cases, in which the cable is below the top surface of the board. Heretofore it has been found necessary for such a double-use blade, even when the blade is used with a cable above the top surface of the board, to be longer than the board so as to overhang the ends thereof so as to provide means ythereon for attaching thereto a cable which may be below the top surface of the board. Customarily, in the first instance the cable is stationary and the blade moves relatively thereto, while, in the second instance, the cable and blade both move together.

The present invention aims to provide a device in which the blade has no overhanging ends and yet is readily convertible for engagement with Y a cable either above or below the top surface of the board.

The invention is desirably inclusive of the device in combination with a drawing board and a blade adapted for interchangeable cable engaging units, as Well as of the respective units themselves.

Other objects and advantages will be apparent from the following description, taken together with the accompanying drawings, in which- Figure 1 is a plan view of a board having a cable above the top surface of the board and with'which one aspect of my present invention is associated;

Figure 2 is an enlarged end portion of my improved blade as shown in Fig. 1 with parts'in plan broken away for clearness of description;

Figure 3 is an enlarged longitudinal section on the scale of Fig. 2 and taken'on the line 3-3 of Fig. 1;

, Figure 4 is a perspective view of one of the cable engaging units for association with the blade of the previous figures;

yFigure 5 is a view similar to Fig. 2, but showing the blade associated with another inter changeable cable engaging unit of my invention; Figure 6 is a longitudinal section on the line 6 6 of Fig. 5; and

Figure 7 is a. perspective View of the cable engaging unit shown associated with the blade in Figs. 5 and 6, the parts of the unit being shown in this figure in temporary separated or exploded relation forvclearness of description.

Referring in detail to the illustrative construction shown in the drawings, II) is a conventional drawing board usually several feet long and which is generally supported upon legs or other pedestal means not necessary to be here shown. The straightedge blade II is superimposed thereon to move toward or away from the draftsman for the purpose of drawing successive parallel lines in various positions of the blade.

As shown in Figures 1, 2 and 3, for maintaining the blade II in successive parallel positions as it is moved on the board, the conventional .cable I2 is provided which is arranged above the top surface of the board about its two end margins and its rear margin. As is well known with such an expedient, the cable I2 is anchored at I3, I3 at the forward corners of the board and then passes up to the blade II where it is entrained through the blade as at I4, the cable runs crossing inv opposite directions and then emerging from the blade to pass up around the idler pulleys I5 at the rear corners of the board. A clamp I6 medially of the rear margin ofthe board prevents movement of the cable with respect to the board. When thus clamped the blade II will move into v,successive parallel positions, and if the angle of the blade is desired tofbe altered the clamp I6 is loosened, the cable permitted to move With respect to the board to accommodate the changed angle 'of the blade, after which the clamp I 6 being tightened the blade will again move into successive paralle positions at the new angle. f

In order to avoid interference, it is desirable to conceal the cable runs which pass through the blade, and this is accomplished in this instance by making my blade of superimposed laminations I'I and I8, both formed desirably of a nonwarping phenolic condensation material secured together as by drive-pins I9. As here shown, the laminations I'I and I8 are each grooved longitudinally to jointly form a channel 20 for the cable I2, one of the laminations, in this instance I'I, being notched laterally as at 2| to provide entrance passages for the cable into the blade.

Since the cable I2 and blade move relatively it is desirable to provide anti-friction cable engaging means adjacent the turns of the cable Within the blade, and in accordance With my present invention I may provide the cable engaging unit 22 shown in perspective in Fig. 4 and lin association with the blade in Figs. 1, 2 and 3, this unit being readily separable from the blade as will next be described.

My improved cable engaging unit 22 shown in Figs. 1 to 4 inclusive comprises a metallic cover plate 22a from and beneath which is suspended a pair of pulley plates 23 between which are inserted the pulley wheels 24 advantageously formed of grooved fiber disks for movement of the cable thereon, the pulley plates with the pulley wheels therebetween being secured together and to the cover plate 22a as by the rivets 25, upon which also the pulley wheels 24 mayrotate.

For the reception of the unitv 22 theblade laminations I'I and I8 are cut away as at 26 and 21 respectively, thus forming a recess whichl communicates both with the entrance passages ZI and the channel and into which the pulley plates and wheels 23-24 are inserted, the pulley wheels substantially coinciding with the cut-out 26 in the lower lamination I1 so as to` be in the plane of the cable as it enters through the passages ZI and turns into the channel 20, the cable runs being entrained by the pulleys 24 as best shown in Fig. 2.

For ready attachment of the unit 22 to the blade, the cover plate 22aI overlaps the recessed portions of the blade laminations and rI have shown holes y28 at the inner end of the unit through which may pass clampingscrews 29 through perforations 36 in the upper lamination I8 and threadedly received in screw sockets 3l in the lower blade lamination I'I. In this position the unit 22 desirably has a depending flange 32 which laps the end of the blade, closing the recess in the blade at this point and providing a desirable finish and protection for the end of the blade. For further securement, somewhat smaller clamping screws 33 may be provided similar to the screws 29 at the outer end of the unit. The screws 33 here pass through openings 22h in the cover plate and 22a and are received rin the screw sockets 22o in the blade. Thus the unit 22 may be readily assembled with or removed from the blade I I by simply loosening the clamping screws 29 and 33.

Turning now to Figs. 5 to '7 of the drawings and as best seen particularly from Fig. 7, I have shown anothercable engaging unit 34 which may be readily used with the straightedge blade I I Where theblade is associated with the drawing board I-Il and with a cable which is below the top surtace of the board.

The cable engaging unit 34 comprises in this instance a cover plate 35, slidable finger-piece 36, and a keeper plate 31. The ringer-piece 36 may be' assembled with the cover plate 35 by having its shank 38 passed through a slot 3-9 in the depending flange 46 of the cover plate. The shank lies in the plane of two offset lugs 4I on the keeper plate. Clamping screws 42 pass through perforations 43 in the cover plate and are threadedly received in screw holes 44 in the keeper plate at each side of the finger-piece shank.

The same screws 2S and 33 which were used with the interchangeable unit 22 may then be used to clamp the unit 34 into the blade at its recessed portion 26, 21. The screws29 pass through the screw openings 35a in the cover plate-35 which register with the screw socketsv 3| in `the blade. Similarly the screws 33 pass through screw openings 35h in the coverlplate Cil ' plates.

finger-piece, the latter desirably has a downward 35 and which register with the screw sockets 22e in the blade. The larger recessed portion 2'I of the blade affords room for movement of the finger-piece, the smaller recessed portion receiving the keeper plate which is substantially of the size and shape of the pulley plate 23 of the unit 22.

By loosening the screws 42 the position of the finger-piece may beI adjusted longitudinally of the=blade to have its outerend 45 extend more or less from the blade, overhanging the-edge of the drawing board, the screws being then tightened to Vmaintain the desired position by clamping the finger-piece shank between the cover and keeper To `limit retractive movement of the bend 46 therein which also places its outer end G3 advantageously below the upper surface of thc blade.

The finger-piece outer end 45 may have a perforation therein fora bolt 48 to which may be'fastened either the cable itself or an adapter such as shown-at 49, the latter in turn carrying a 'clamping device such as 56 for engagement withthe cable, as at 5I, where the cable is entirely beneath the board I0.

It will be understood that therel are 'a pair of cach of the units 22 and 3`4for theK blade II, and that' theV construction of the blade is similar at each end to receive either of the units of either pair and so as to be completely interchangeable.

Thus-thc blade may be sold With the units 22 assembled therewith, for exampla'andthe purchaser may alsopurchase a set of the units 33 for friture use with the blade, orhe may purchase suchunits 34 after he has been using the blade forfsome time Withthe units 22. In either case therea'dy 'convertibility of the blade for use with eitlier typefof cablewill be apparent and its many advantages manifest in reducing the equipment which the draftsman must have on hand and simplifying its use.

The invention is not limited-to details-of construction shown for purposesvofexemplication. Alsditlis not essential that all features of the invention be used conjointly, as various combina tion-s and sub-combinations may be advantageously employed- I claim:

l. A parallel` straightedgc deviceembcdyi'ng a bladefhaving'arecess atl its end including a cable engaging unit for assembly with the blade of the device and comprising a cover plate completely covering said recess, a cable engaging member carried by and movable in said recess'beneath saidcover 'plata/said cover plate having ya depending` flange adapted to lap the end of the blade and being provided withholes about its-margin ther-editor reception of attachment screws, and passagesrinthe cover plate for the reception of attachment elements for the cable engaging mem-ber.

2. Aparallel straightedge deviceincluding a cable engaging unit for assembly with the blade of the device and comprising a 'cover plate, said cover plate having a depending flange adapted to lap the end of the blade and being provided with. holesabout the margin thereof for reception `of attachment screws, a slot in` said flange, a nger-piece movable in said` slot longitudinally ofv the. blade, andl clamping means carried by the cover plate for xing the longitudinal position of.` the :lnger-'piecal said `clamping means comprising a keeper suspended'byscrews from and beneath said cover plate, the screws -being adapted to be tightened to clamp the shank of the finger-piece between the keeper and the cover plate.

3. A parallel straightedge device including a cable engaging unit for assembly with a blade having an end recess, said cable engaging unit comprising a metallic cover plate, said cover plate having a depending ange adapted to lap the end of the blade and being provided With fastening means about its margin for attachment to the blade, a pair of spacedl apart pulley plates carried by and suspended from said cover plate, and a pair of pulley wheels rotatably carried between said pulley plates, said pulley plates and pulley wheels being adapted to be received in the recess in the blade and said depending flange lapping the end of the blade to close said recess.

. HAROLD L. DE LISLE. 

